The aim of this study was to identify the factors which can affect the efficacy of corticosteroid (CORT) therapy in the management of hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. Research articles reporting the efficacy of CORT therapy to HELLP syndrome patients were searched in several electronic databases including EMBASE, Google Scholar, Ovid SP, PubMed, and Web of Science. Study selection was based on predefined eligibility criteria. Efficacy was defined by the changes from baseline in HELLP syndrome indicators after CORT therapy. Meta-analyses were carried out with Stata software. Data of 778 CORT-treated HELLP syndrome patients recruited in 22 studies were used in the analyses. Corticosteroid treatment to HELLP syndrome patients was associated with significant changes from baseline in platelet count; serum levels of aspartate aminotransaminase, alanine transaminase, and lactic dehydrogenase (LDH); mean blood pressure; and urinary output. Lower baseline platelet count predicted higher change in platelet count after CORT therapy. Lower baseline platelet count and lower baseline urinary output predicted greater changes in LDH levels after CORT therapy. There was also an inverse relationship between the change from baseline in LDH levels and intensive care duration. Higher CORT doses were associated with greater declines in the aspartate aminotransaminase, alanine transaminase, and LDH levels. Incidence of cesarean delivery was inversely associated with the gestation age. The percentage of nulliparous women had a positive association with the intensive care stay duration. High-dose CORT therapy to HELLP syndrome patients provides benefits in improving disease markers and reducing intensive care duration, especially in cases such as mothers with much lower baseline platelet count and LDH levels.